蒙古羊成纤维细胞系的染色体核型分析

通过对蒙古羊成纤维细胞系染色体核型分析得出,蒙古羊的核型为2n=54,结果表明染色体核型符合本品种的要求。     

浙江省农民农药施用行为调查分析与对策思考

根据对浙江省52个县(市、区)4 828户农民施药行为的调查结果,基本掌握了全省农民用药状况和用药行为的现状,从提高农药使用者的防治水平、创新植保服务方式的角度,提出了改进的对策。     

农户化肥减施意愿与行为研究进展

科学推进化肥减量任务是控制面源污染、推动乡村生态振兴、促进农业可持续发展的关键.通过梳理国内外相关文献发现,我国化肥过量施用现象仍普遍存在,化肥减施潜力大.农户作为我国化肥的主要施用者,也是环境污染防治过程中的主要参与者,但农户对过量施肥的认知不足,这增加了环境污染的风险.此外,农户化肥减施意愿与行为之间存在高意愿低行...     

福建省农地流转后农户经营行为差异的实证分析

以福建省为例开展入户问卷调查，按农户在流转中不同的地位进行分类，对流转过程中农户的意愿和行为差异以及农地流转后农户分化所形成的农业经营格局进行分析，结果发现：土地从年龄较大、老年人口较多的贫困家庭以及较为年轻化的富裕家庭流出，向家庭经济状况较差的年轻化家庭流入；农地流转多以口头实现；在农村实际发生的农地流转规模远高于官方统计数字。     

炼山后杉木幼林生长动态研究

本文通过连续四年定位研究,结果表明:炼山能明显地提高杉木造林成活率;对幼林生长有促进效应,但这种效应仅是短期的,一般在炼山后第一年至第三年;炼山还有利于一年生草本和阳性植物种类增加。     

铝（Al^3＋）对洋葱根生长和细胞分裂的影响

以洋葱(Allium cepa L.2n=16)为材料,研究不同浓度氯化铝(AlCl_3·6H_2O)溶液对根生长、根尖细胞有丝分裂和染色体形态的影响.研究结果表明,随着Al~(3+)浓度的增加,根的生长量递减,呈明显的负相关;随着处理时间的延长,每单位时间的生长量亦递减,甚至停止生长;在50～200ppm Al~(3+)处理下,根尖细胞有丝分裂指数随着Al~(3+)浓度增高而递减,随着处理持续时间的延长而递减;不同浓度的Al~(3+)处理都能引起染色体畸变,如,c-有丝分裂、染色体桥、染色体粘连等;恢复培养后各处理的鳞茎均能恢复生长.染色体畸变率降低.     

Perceptions of Whooping Cranes among waterfowl hunters in Alabama: using specialization,awareness, knowledge,and attitudes to understand conservation behavior

A central component of successful wildlife conservation is the understanding of public perceptions toward a species. We administered an online survey to Alabama waterfowl hunters (n = 284) to examine differences in awareness and knowledge of and attitudes toward Whooping Cranes. We investigated if these variables and/or birding specialization influenced likeliness to participate in conservation behaviors. Specialization level was positively related to awareness, knowledge, and conservation attitudes. Respondents with greater knowledge and favorable attitudes toward cranes were more likely to donate to a hypothetical crane conservation fund, and expert birdwatchers were more likely to belong to a birding organization than novice or intermediate birdwatchers. Our research supplements existing birding specialization literature by incorporating cognitive variables specific to Whooping Cranes. Findings suggested that enhancing knowledge regarding Whooping Crane conservation may be an advantageous strategy for promoting conservation and positive behaviors toward the species.     

Effects of tail docking and/or teeth clipping on behavior,lesions, and physiological indicators of sows and their piglets

To evaluate effects of tail docking and/or teeth clipping on sows and their piglets, a total of 24 sows and their 302 piglets at 3 days of age were randomly allocated to one of four treatments: teeth clipping and tail docking (TCTD), teeth clipping (TC), tail docking (TD), or intact teeth and tail (Intact). Behavior of piglets and sows, lesions on the body and tail of piglets and sows' teats were inspected. Heart rates of processed piglets were increased (p < .01) during the procedures. Teeth clipping decreased body surface temperature (p < .01) of piglets during and after the procedures but tail docking did not (p > .01). Processed piglets spent more (p < .05) time lying alone and playing/fighting than sham‐processed piglets. Tail docked piglets spent less (p < .01) time standing than tail sham‐docked piglets. Intact teeth increased (p < .05) the avoidance behaviors of sows. Teeth clipping decreased (p < .05) the lesion scores on the anterior, middle, and posterior teats. Taken together, piglet teeth clipping had more impact on sows and their piglets than tail docking did in the lactation period based on our findings.     

An allelopathic substance isolated from Zanthoxylum limonella Alston fruit

Bioassay-guided fractionation of the ethyl acetate extract of the Zanthoxylum limonella Alston fruits led to the isolation of a phenolic compound named xanthoxyline. The allelopathic effects of xanthoxyline were evaluated on Chinese amaranth (Amaranthus tricolor L.) and Barnyardgrass (Echinochloa crus-galli (L.) Beauv.) under laboratory conditions. At a concentration of 2500 μM, xanthoxyline completely inhibited seed germination and growth of Chinese amaranth, while this compound showed a significantly inhibitory effect on seed germination of Barnyardgrass by 43.59% and inhibited shoot and root length by 71.56% and 87.48%, respectively. To determine the mechanism through which xanthoxyline exerts its toxicity, the cytogenetic bioassay was conducted. Roots of Allium cepa L. (onion) were treated with a series of concentrations, ranging from 15.625 to 125 μM for 18 h. Cytogenetic studies of onion roots showed a decrease of the mitotic index in the exposed roots dependent on the concentration of xanthoxyline. Likewise, the mitotic phase index was altered in onion incubated with xanthoxyline. Analyses of the abbreviation types showed spindle disturbances at late prophase, sticky metaphase, c-mitosis, non-oriented chromosome at metaphase, sticky anaphase, delayed anaphase and diagonal at telophase for the onion roots exposed to xanthoxyline.     

小麦细胞分裂素氧化/脱氢酶基因（TaCKX5）的克隆及其染色体定位

【目的】克隆小麦的TaCKX基因并对其序列进行生物信息学分析,明确TaCKX基因在小麦基因组中的分布情况,以期为今后深入研究小麦CKX基因以及利用该基因进行小麦重要农艺性状的遗传改良奠定基础。【方法】采用同源克隆结合BAC文库筛选的方法克隆基因,通过小麦缺体-四体对其进行染色体定位。【结果】从普通小麦中国春中分离得到TaCKX5基因的gDNA和cDNA序列。分析表明,TaCKX5基因的开放阅读框为1 596 bp,编码531个氨基酸,含有CKX基因家族典型的功能位点FAD-binding domain,预测属于分泌蛋白,并具有糖基化位点。使用中国春缺体-四体将TaCKX5定位于小麦第三同源群。系统发育分析表明,CKX基因在植物中较为保守,禾谷类作物中直向同源的CKX基因很可能具有相似的特性与功能。【结论】分离获得了普通小麦TaCKX5基因全长,TaCKX5分布于小麦染色体3A、3B、3D上,与水稻OsCKX5基因直向同源。